System and method for component centering

ABSTRACT

A technique facilitates positively centering a well component, e.g. a downhole tool and/or coiled tubing, inside a pressure barrier, e.g. a riser. A centering device is positioned along the pressure barrier to move the well component toward a center of the pressure barrier. The centering device has a movable member, e.g. a plurality of movable members, selectively shiftable between a radially outward position and a radially inward position within the pressure barrier component. The well component is moved toward the center of the pressure barrier during shifting of the movable member(s) toward the radially inward position.

BACKGROUND

In many types of oilfield applications, downhole tools are conveyed downhole via conveyance systems, e.g. coiled tubing, and used to perform measurements and services in wells. The downhole tools and conveyance systems tend to be relatively long, thin components deployed downwardly into a wellbore. To facilitate deployment downhole, the downhole tools may be placed in a long riser via the coiled tubing. The downhole tools enter through the top of the riser and are either pulled to the bottom of the riser or assembled into the riser. The riser is then attached to the well and pressure tested so the downhole tools may be run downhole into the wellbore. However, the coiled tubing is not straight and often has a residual bend which can produce thousands of pounds of radial force that effectively moves the downhole tools and/or coiled tubing off the well center.

Consequently, attempts have been made to center the downhole tools and/or coiled tubing by, for example, a combination of approximately straightening the coiled tubing using brute force and pulling on the downhole tool by hand or via come-alongs. When using coiled tubing, connection of the coiled tubing with the downhole tool may be made with a coiled tubing injector hanging from a crane above the downhole tool, thus providing some flexibility. However, neither the crane nor the injector is able to provide precise positioning. The pulling force on the coiled tubing from the coiled tubing reel produces substantial torque which causes the entire system to hang at a slant. Even with the use of a riser, such forces tend to tilt or move the downhole tool and/or coiled tubing off-center with respect to the well.

SUMMARY

In general, the present disclosure provides a system and methodology for positively centering a well component, e.g. a downhole tool and/or coiled tubing, inside a pressure barrier component, e.g. a riser. A centering device is positioned along the pressure barrier component to center the well component with respect to the pressure barrier and the well. The centering device has a movable member, e.g. a plurality of movable members, which may be selectively shifted between a radially outward position and a radially inward position with respect to the pressure barrier component. The movable members are oriented to engage the well component and to move the well component toward a center of the pressure barrier as the movable members are shifted radially inward.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate various implementations described herein and are not meant to limit the scope of various technologies described herein, and:

FIG. 1 is a schematic illustration of an example of a well system utilizing a centering device in combination with a pressure barrier, according to an embodiment of the disclosure;

FIG. 2 is a schematic cross-sectional view of the centering device taken generally along line 2-2 in FIG. 1, according to an embodiment of the disclosure;

FIG. 3 is a schematic illustration of another example of a well system utilizing a centering device in combination with a pressure barrier, according to an embodiment of the disclosure;

FIG. 4 is a schematic cross-sectional view taken generally along line 4-4 of FIG. 3, according to an embodiment of the disclosure;

FIG. 5 is a schematic illustration of another example of a well system utilizing a centering device in combination with a pressure barrier, according to an embodiment of the disclosure;

FIG. 6 is a schematic cross-sectional view taken generally along line 6-6 of FIG. 5, according to an embodiment of the disclosure;

FIG. 7 is a schematic illustration of another example of a well system utilizing a centering device in combination with a pressure barrier, according to an embodiment of the disclosure;

FIG. 8 is a schematic illustration of another example of a well system utilizing a centering device in combination with a pressure barrier, according to an embodiment of the disclosure;

FIG. 9 is a schematic illustration similar to that of FIG. 8 but with the centering device in a different operational position, according to an embodiment of the disclosure;

FIG. 10 is a schematic illustration of another example of a well system utilizing a centering device, according to an embodiment of the disclosure; and

FIG. 11 is a schematic illustration similar to that of FIG. 10 but with the centering device in a different operational position, according to an embodiment of the disclosure.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of some illustrative embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

The disclosure herein generally relates to a system and methodology for positively centering a well component inside a pressure barrier to facilitate assembly and/or deployment of a well string into a well. By way of example, the well component may comprise a downhole tool and/or coiled tubing and the pressure barrier component may comprise a riser of the type used in helping transition downhole tools from a supply vehicle to the inside of a wellbore. Deployment into the wellbore is facilitated by a centering device positioned along the pressure barrier component and arranged to center the well component with respect to the pressure barrier component and the well.

The centering device may comprise various mechanisms by which it is mounted along the pressure barrier component, e.g. riser. Additionally, the centering device comprises a movable member, e.g. a plurality of movable members, selectively shiftable between a radially outward position and a radially inward position within the pressure barrier component. The movable members are oriented to engage the well component, e.g. downhole tool and/or coiled tubing, and to move the well component toward a center of the pressure barrier. The movable member(s) may be selectively shifted to engage the well component and to move the well component to a desired radially inward position.

Depending on the type of deployment operation, the centering device may be constructed for use with a variety of well components. Additionally, the centering device may be utilized according to techniques which facilitate coupling and/or deployment of well components downhole. In oilfield applications, a wide variety of tools may be utilized and the length of such tools depends on the function or functions they are to perform. The tools often have substantial length which presents challenges with respect to installing the downhole tool while maintaining well control.

Some well operations use a riser in combination with a blowout preventer (BOP) to facilitate deployment of the desired downhole tools while also maintaining a pressure barrier for well control. For example, in coiled tubing, wireline, and slick line services, downhole tools are transferred from a supply vehicle to the wellbore by using a relatively long riser and by deploying the downhole tool into a top of the riser by a conveyance, e.g. coiled tubing. The downhole tools may be pulled into the bottom of the riser or assembled into it, and then the riser is attached to well equipment, e.g. to a blowout preventer, at the top of a wellbore. Once attached, the riser may be pressure tested and the downhole tools may be run into the well. In this technique and others, a centering device or devices (as described herein) facilitates alignment of the downhole tool and/or coiled tubing with the wellbore. As a result, the centering device or devices also facilitate deployment and/or movement of the downhole tool/coiled tubing along the riser and the wellbore.

In another application, an easier-to-run conveyance, e.g. wireline or slick line, is used to place the downhole tools in the well and then a harder conveyance, e.g. coiled tubing, is used to run the downhole tool farther into the wellbore. In this latter methodology, the downhole tools may be deployed with the aid of an additional part in the form of a deployment bar. The deployment bar provides a surface which is readily gripped and sealed against by the blowout preventer. Generally the diameter of the deployment bar is selected to match the diameter of the coiled tubing used to deploy the tool downhole. To enable closure of master valves while the downhole tool or tools are hanging in the blowout preventer and without opening the well to atmosphere, the deployment bar is sheareable by shear rams in the blowout preventer. After shearing, the slip and pipe rams of the blowout preventer can be opened and the downhole tool may be dropped into the well.

Because the coiled tubing has residual bend which can apply substantial radial force, difficulties arise in connecting the coiled tubing or other hard service to the downhole tool hanging in the blowout preventer. However, by using a centering device or devices as described herein, the downhole tools and/or coiled tubing may be centered to facilitate coupling, alignment with the wellbore, deployment, and/or movement of the downhole tool/coiled tubing along the riser and the wellbore.

Referring generally to FIG. 1, an embodiment of a well system 20 is illustrated as comprising a centering device 22 used in combination with a pressure barrier component 24. By way of example, the pressure barrier component 24 may be a riser 26 or other tubular string. The centering device 22 may be mounted along the tubing string/riser 26, and a well component 28, e.g. a downhole well component, may be deployed down through an interior 30 which extends along the interior of pressure barrier component 24 and centering device 22. In a variety of applications, the interior 30 may be an extension of a wellbore 32 which extends into a geological formation beneath a wellhead or other well equipment 34.

Depending on the application, the well equipment 34 may comprise various types of equipment and/or may be used in combination with other devices, such as a blowout preventer 36. In the illustrated example, blowout preventer 36 comprises a plurality of blowout preventer rams 38. The rams 38 may be constructed in various configurations and may be utilized for sealing against well component 28 and/or cutting through well component 28. By way of example, well component 28 may comprise various tools and/or conveyances, such as slick line, wireline, or tubing. In the embodiment illustrated, well component 28 comprises tubing 40, e.g. coiled tubing, having a hollow interior passage 42.

Referring again to FIG. 1, the centering device 22 also may be constructed in various configurations with components selected for a given application. In the example illustrated, the centering device 22 comprises a mounting structure or block 44 through which a plurality of movable members or centering elements 45 is mounted. In the embodiment illustrated, centering elements 45 are in the form of pins 46. The pins 46 may be oriented in a generally radial direction for selective engagement with the well component 28, e.g. coiled tubing 40, to enable centering of the well component 28 within interior 30 of pressure barrier component 24.

By way of example, the pins 46 may be threadably engaged with mounting structure 44 via threaded regions 48. This allows individual pins 46 to be moved radially inward and into engagement with well component 28 via rotation of the pins. Continued rotation of pins 46 forces the well component 28 to a desired position, e.g. a centered position, within interior 30.

Additionally, various structures may be used to mount centering device 22 along the pressure barrier component 24. In the illustrated example, the mounting structure 44 is shaped as a ring and is positioned between flanges 50 of adjacent sections of the riser 26. The flanges 50 may have appropriate grooves and seals oriented to seal against mounting structure 44 as the flanges 50 are tightened against mounting structure 44 by suitable fasteners. Suitable fasteners comprise threaded fasteners extending in a generally axial direction through the flanges 50 and mounting structure 44.

The number of centering pins 46 may vary depending on the parameters of a given application. As illustrated in the cross-sectional view of FIG. 2, for example, four pins 46 may be used to center well component 28. However, other numbers of pins 46, e.g. 3-8 pins, may be used depending on, for example, the relative diameters of interior 30 and coiled tubing 40 or other well component 28. A minimum number of pins 46 may be selected such that the spacing between adjacent pins is close enough to enable centering of the well component 28 without trapping the well component 28 between pins 46. By way of example, centering a well component 28 may comprise positioning component 28 along a centerline of pressure barrier component 24.

In some applications, the pins 46 may be controlled hydraulically by a suitable hydraulic system 52, as illustrated by dashed lines in FIG. 2. In this type of embodiment, the pins 46 may be driven linearly by, for example, hydraulic pistons rather than being threadably engaged with mounting block 44. The hydraulic system 52 may be constructed to actuate pins 46 independently and/or collectively. In some applications, the pins 46 may be pressure balanced versus wellbore pressure by providing a suitably sized annular shoulder having an area equal to the pin area exposed to wellbore pressure on one side and atmospheric pressure on the other side. Additionally, the pins 46 may each have grooves, tail rods, or other indicia to provide a visual indication as to the extent of their radial movement into interior 30.

Referring generally to FIGS. 3 and 4, another embodiment of a well system 20 and centering device 22 is illustrated. In this example, the well component 28, e.g. coiled tubing 40, is centered within interior 30 via centering elements 45 in the form of a plurality of centering arms 54. The centering arms 54 may be pivoted inwardly to engage the well component 28 and to shift the well component 28 to a desired position, e.g. a position aligned with a center axis of interior 30. In some embodiments, the centering arms 54 may be staggered to provide a non-trapping closure similar to a camera iris.

By way of example, the centering arms 54 are mounted on pivot pins 56 which may be collectively or individually rotated to shift their corresponding centering arms 54 to a desired position with respect to interior 30. As illustrated in FIG. 3, the pivot pins 56 may be oriented in a generally axial direction with respect to riser 26 and rotatably received in a housing 58 of centering device 22. The housing 58 may be connected to pressure barrier component 24 by suitable flanges, threaded engagement, or other suitable connection devices and techniques. Additionally, seals 60, e.g. O-ring seals, may be positioned between housing 58 and each pivot pin 56.

As illustrated by arrows 62 in FIG. 4, rotation of pivot pins 56 causes the corresponding centering arms 54 to pivot in a radially inward direction into interior 30. Continued rotation of pivot pins 56 moves the centering arms 54 into contact with well component 28 so as to shift the well component 28 to a desired position. Depending on the application, the pivot pins 56 may be rotated manually or with a suitable hydraulic or electro-mechanical actuator.

Referring generally to FIGS. 5 and 6, another embodiment of a well system 20 and centering device 22 is illustrated. This embodiment is similar to the embodiment described above with reference to FIGS. 3 and 4 in that the well component 28, e.g. coiled tubing 40, is again centered within interior 30 via a plurality of centering arms 54. Similar to the previously described embodiment, the centering arms 54 may be pivoted inwardly to engage the well component 28 and to shift the well component 28 to a desired position. However, the centering arms 54 are mounted on pivot pins 56 which are oriented in a generally lateral direction (see FIG. 6), e.g. generally perpendicular to riser 26, rather than a generally axial direction.

The pivot pins 56 may be collectively or individually rotated to shift their corresponding centering arms 54 to a desired position with respect to interior 30. As illustrated by arrows 64 in FIG. 5, rotation of pivot pins 56 causes the corresponding centering arms 54 to pivot along the length of well component 28 and into engagement with well component 28. Continued pivoting of centering arms 54 effectively shifts the well component 28 to a desired position. Depending on the application, the pivot pins 56 may be rotated manually or with an actuator, e.g. a suitable hydraulic or electro-mechanical actuator.

Referring generally to FIG. 7, another embodiment of well system 20 is illustrated with centering device 22 positioned along pressure barrier component 24. In this embodiment, the centering elements 45 again comprise pins 46 oriented generally radially toward well component 28. However, the pins 46 are hydraulically actuated via corresponding hydraulic pistons 66. Each hydraulic piston 66 may be located at an outlying end of the corresponding pin 46 and positioned within a hydraulic cylinder 68.

By way of example, each hydraulic piston 66 may be sealed with respect to an internal surface of the hydraulic cylinder 68 via a piston seal member 70. Additionally, the corresponding pin 46 may be sealed with respect to the centering device housing 58 via a seal member 72. Hydraulic actuating fluid may be introduced into hydraulic cylinders 68 under the control of hydraulic system 52 so as to enable the desired radial shifting of corresponding pins 46 with respect to interior 30 and well component 28.

In some embodiments, a rolling element 74, e.g. a wheel or roller, may be rotatably mounted at an opposite end of each pin 46 relative to the hydraulic piston 66. The rolling elements 74 may be oriented for engagement with the well component 28, e.g. coiled tubing 40, when the pins 46 are actuated inwardly via hydraulic pistons 66. As illustrated, the rolling elements 74 may be positioned so as to roll as well component 28 moves axially along interior 30. This type of arrangement facilitates axial movement of the well component 28 while engaged and centered via pins 46 of centering device 22. As with other embodiments described herein, the pins 46 may be actuated individually and/or collectively.

Referring generally to FIGS. 8 and 9, another embodiment of well system 20 is illustrated with centering device 22 positioned along pressure barrier 24. In this example, however, the centering elements 45 are in the form of an expandable element 76, e.g. expandable elastomeric elements. The expandable element 76 may be in the form of, for example, inflatable elements or compressible elements. In some embodiments, the expandable element 76 may be a single ring or other structure which is selectively inflated or compressed in a manner which causes it to act against well component 28.

In the specific embodiment illustrated, the expandable element 76 may comprise a single element or a plurality of elements disposed between compression rings 78 contained within an internal recess 80 of centering device 22. At least one of the compression rings 78 is oriented for engagement with a piston 82. By way of example, the piston 82 may be in the form of a hydraulic piston positioned in a corresponding hydraulic piston cylinder 84 and sealed along the cylinder 84 via a plurality of seals 86. The element or elements 76 may each comprise elastomer materials, or at least one of the elements may comprise an elastomer material and other elements may comprise metallic or plastic materials. Such a combination of elastomer elements with metallic and/or plastic elements can alter the way the elements move under load, improving the durability, or reducing the friction.

The piston 82 may be oriented for movement in a generally axial direction into engagement with the adjacent compression ring 78. As the piston 82 is moved against compression ring 78 and toward the expandable element 76, the expandable element 76 is compressed in an axial direction. The axial compression forces the expandable element 76 to bulge or expand in a radially inward direction and into engagement with well component 28, as illustrated in FIG. 9. Continued compression of the expandable element or elements 76 forces the well component 28 to a more centralized position within interior 30. As illustrated, the expandable element 76, compression rings 78, and piston 82 may be constructed to allow linear movement of well component 28 therethrough. Movement of piston 82 may again be controlled by a suitable hydraulic system 52 or other actuation system which enables selective actuation of the piston 82.

Referring generally to FIGS. 10 and 11, another embodiment of centering device 22 is illustrated. In this example, centering elements 45 are again in the form of pins 46 oriented through mounting structure 44 for engagement with well component 28. The pins 46 may be oriented in a generally radial direction with respect to interior 30 and controlled via a cam mechanism 88. In the embodiment illustrated, cam mechanism 88 has an internal cam profile 90 engaged by cam followers 92, e.g. rollers, disposed at the outlying ends of pins 46. As the cam mechanism 88 is rotated, the cam profile 90 forces pins 46 to slide in a radially inward direction and into engagement with well component 28, e.g. coiled tubing 40. Continued rotation of cam mechanism 88 effectively causes pins 46 to force the well component 28 toward a centered position within interior 30, as illustrated in FIG. 11.

In the embodiment illustrated, cam mechanism 88 is in the form of a cam ring which is rotated to shift pins 46 to a desired radial position. The cam ring 88 may be rotated by a suitable actuator, such as a hydraulic piston actuator, a worm gear, a solenoid, or another suitable actuator. The cam profile 90 as well as the cam followers 92 may be adjusted to achieve desired movement of pins 46.

Accordingly, centering device 22 may comprise a variety of centering element(s) 45 able to move the well component 28 to a desired position at or toward the center of interior 30. The centering element(s) 45 may comprise radially oriented pins, arms mounted on pivot pins, inflatable elements, compressible elements, or other suitable elements that may be selectively actuated. Additionally, the centering elements may be actuated hydraulically, mechanically, electro-mechanically, or by other suitable techniques. The pins 46 or other types of centering elements 45 may comprise various end configurations to facilitate engagement with the tool component 28. Examples of such end configurations comprise V-blocks, V-shaped rollers, wheels, curved ends, expanded ends, and/or other suitable end configurations which facilitate non-trapping engagement with well component 28.

Additionally, the overall well system 20 may have a variety of configurations for use in many types of well operations. Similarly, the size and configuration of the centering device 22 as well as the pressure barrier component 24 may be selected according to the parameters of a given operation. For example, the pressure barrier component 24 may comprise various types of risers 26 or other components mounted for cooperation with various blowout preventers or other well equipment. The well component 28 may be in the form of coiled tubing, other types of tubing, cable, downhole tools, or other well components disposed in an/or passed through the pressure barrier component 24.

Although a few embodiments of the system and methodology have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. 

1. A system for positive centering during a well operation, comprising: a pressure barrier component through which a non-rotating well component is deployed; and a centering device positioned along the pressure barrier component for selective engagement with the well component to move the well component toward a center of the pressure barrier component, the centering device having a plurality of movable members selectively shiftable between a radially outward position and a radially inward position within the pressure barrier component, the movable members being oriented to engage the well component and to move the well component within the pressure barrier component when the movable members are shifted to the radially inward position.
 2. The system as recited in claim 1, wherein the pressure barrier component comprises a riser.
 3. The system as recited in claim 2, wherein the non-rotating well component is selected from the group consisting of coiled tubing and a downhole well tool.
 4. The system as recited in claim 1, wherein the plurality of movable members are sized and positioned to prevent the passage of the well component between any two of the plurality of movable members.
 5. The system as recited in claim 1, wherein the movable members comprise pins oriented for movement in a radial direction.
 6. The system as recited in claim 5, wherein the pins are pressure balanced between internal pressure and external pressure acting on the pressure barrier component.
 7. The system as recited in claim 1, wherein the movable members comprise centering arms mounted on pivot pins.
 8. The system as recited in claim 5, wherein the pins are collectively actuated.
 9. The system as recited in claim 5, where the pins are actuated by a cam mechanism.
 10. The system as recited in claim 1, wherein the movable members comprise at least one expandable element.
 11. The system as recited in claim 10, wherein the at least one expandable element comprises a compressible elastomeric element.
 12. A system, comprising: a centering device having a mounting structure configured for mounting along a riser extending above a wellbore, the centering device comprising a centering member selectively shiftable between a radially outward position and a radially inward position, the centering member being oriented to engage and move a non-rotating well component toward a center of the riser while the well component is deployed through the centering device.
 13. The system as recited in claim 12, wherein the centering member comprises a plurality of pins oriented in a radial direction.
 14. The system as recited in claim 12, wherein the centering member comprises a plurality of centering arms mounted on pivot pins.
 15. The system as recited in claim 12, wherein the centering member comprises a radially expandable elastomeric element.
 16. The system as recited in claim 13, wherein the pins have outer ends engaged by a cam mechanism operable to shift the pins between the radially outward position and the radially inward position.
 17. A method, comprising: providing a centering device with a plurality of movable members; mounting the centering device along a riser; deploying a coiled tubing into the riser; and centering the well component toward an axis of the riser by selectively actuating the movable members against the well component.
 18. (canceled)
 19. The method as recited in claim 17, wherein centering comprises actuating radially oriented pins in a radially inward direction to engage and move the coiled tubing.
 20. The method as recited in claim 17, wherein centering comprises collectively moving the movable members to a radially inward position within the riser.
 21. The method as recited in claim 17, wherein centering facilitates coupling the coiled tubing to a downhole tool. 